Printing plate



April 16, 1940.

H. A. sKov PRINTING PLATE I Fil ed Jan. 51. 1939 2 Sheets-Sheet 1 A ril16, 1940. I

Filed Jan. :51, 19:9

H. A. sKov 2,197,084

PRINTING PLATE 2 Sheets-Sheet 2 Fig.6

I responding to that of the cylinderstill have- Patented Apr. 16, 1940UNITED STATES- P'ATENT o1=1=1cE Application January 31, 1939, Serial No.253,898 In Denmark June 8, 1838 10 Claims. (01. lei-401.1

The invention relates to a method to apply type forms or the likeprinting means to rotary press cylinders and to a device for carryingout the said method.

In the following specification and claims the expression type form"comprises other suitable printing means. a

In rotary and corresponding printing machines printing with rotaryprinting forms the forms are subjected to a deformation if the type formis bent to suit the printing cylinder.

Owing to this bending the printing surface of the type form is deformed,as its dimensions in the direction of the axis of the printing cylinder.are unchanged, but it is stretched in the circumferential direction.

This deformation of the printing surface is of no importance in theprinting of newspapers and the like, but it prevents the printinginrotary presses by normal methods of such printed matters as e. g.drawings, maps and the like, upon'which precise measurements areafterwards v to be taken, or matters which for other reasons must be soexact that the printing surface of the type form must not be subjectedto extension in one direction owing 'to the above mentioned bending ofthe type form to suit it to the printing cylinder.

Printing 'forms. are known intended for attachment on printingcylinders, which printing forms-although shaped with a curvature coracorrect printing surface. These printing forms are mainly intended foruse in connection with printing on a single press having both one flatand one or more cylindrical printing surfaces intended for muiti-colourwork. The production of such printing forms is complicated and presumesthat the printing surface is an electrotype shell or the like.

It is further known to produce printing plates made of rubber andintended for use on rotary printing presses. When producing theseprinting plates, the matrix from which the plates are molded is bent sothat the printing image thereon contracts a little. The rubber plate isthen produced so as to correspond to the compressed printing surface onthe matrix, and the rubber is vulcanised. The printing plate thusproduced and consisting of rubber will, when applied on the printingcylinder, be subjected to such a deformation that the printing-surfaceis stretched, thereby becoming correct.

The present invention purports the elimination of the difficultiesattaching to the aforementioned processes.

According to the present invention, a plane,

type form, for example a rubber printing plate, is used. This type formis according to the invention aflixed to the curved outer side of acarrier consisting of resilient material, thus imparting to theoriginally plane type form a deformation resulting in a stretching ofthe printing surface. The said carrier with the attaching type form isthen aflixed to the printing cylinder. According to the invention thecarrier possesses a rear face shaped in such a manner for examplecurved-that the carrier, when the rear face is pressed home so as to lieup against the outer surface of the printing cylinder, will of its ownaccord bend in such a manner that the printing surface of the type formwill thereby be compressed (staved). Thereby the stretching imparted tothe printing surface of the type form through being affixed to thecurved outer surface of the carrier is neutralised.

In practice, for example, the type form may be made in the shape of arelatively thin plane plate, one side of which forms the printingsurface while its rear side is intended to be secured to a carrier, theouter surface of which forming part of a cylindrical surface ofrevolution, the radius of curvature of which is shorter than desired forthe printing surface during the printing operation, and if the rear faceof the carrier is at the same time shaped as part of a cylindricalsurface of rotation with a still shorter radius of curvature than thatof the outer surface, it will be possible to nullify, at the fixation ofthe carrier to the printing cylinder, the deformation which the printingsurface got when the type form was applied to the outer surface of thecarrier. There are no practical difficulties in suiting the radius ofcurvature for the outer surface and the rear surface of the carrier inrelation to one another and to the radius of curvature of the printingcylinder in such a way that the printing surface will be correct whenthe carrier with the type form thereon is applied to the printingcylinder.

In practice the shape and dimensions of the carrier may profitably besuited to the print to be produced; it may e. g. be a column of anewspaper or only a single small sheet, such as e. g. a label, atrade-mark or the like. When printing newspapers, preferably a pluralityof carriers with printing surfaces are employed, each printing a column.Whether the carrier be long or short in the longitudinal directic-n ofthe printing cylinder, reinforcements (or only one at predeterminedmutual distances.

The accompanying drawings show, by way of a" practical example, what isnecessary to make the invention understood, the example chosen being adevice which may be used in the printing of newspapers or the like. I

Fig. l is an end view of part of a printing cylinder with a number ofcarriers amxed thereon, of which the left hand and centre carriers areof identical shape, whereas the right hand carrier is shown in amodified constructional form,

Fig. 2 is a plan view of one of the carriers shown in Fig. 1,

Fig. 3 is a cross-section through a carrier and the type form mountedthereon and of the printing cylinder, to which the carrier is secured bymeans of a securing bolt,

Figs. 4 and 5 illustrate that the printing cylinder may be shapedotherwise than as a cylindri-= cal su'rfaceof revolution, r

Fig. 6 is a schematical side view of a printing machine for industrialuse, and

Fig. 7 is the printed product in larger scale.

Referring now to Figs. 1, 2 and 3, I is the printing cylinder, thecylindrical outer surface of which is designated by v. 2 designatescarriers, and considering the left one in Fig. 1 it will be seen thatits outer surface 3 forms part of a cylindrical surface of revolution.The radius of curvature R of this surface is shorter than the radius ofcurvature T which the printing surface t is desired to have during theprinting operation. The radius of curvature T in Fig. 1 Y must beimagined to end at the same or practically the same point as the radiusof curvature V of the outer surface 1) of the printing cylinder, namelyat a point representing the axis of the printing cylinder. The rear face17 of the said carrier forms part of a cylindrical surface ofrevolution, the radius of curvature r of which is still shorter than theradius of curvature R of the outer surface 21. To the surface 1 of thecarrier is applied (e. g. stuck) a type form 3, which must be imaginedto consist of a relatively thin plate of a flexible material, e. g.,caoutchouc or a weak metal. The outer surface of the type form formstheprinting, surface, which will, therefore, be more or less broken.

When the type form 3 is stuck or otherwise applied to the outer. surface11 of the carrier, the printing'surface (which was when produced planeand, therefore, correct) of the type form will be deformed in onedirection, as at its sticking to the carrier 2 an extension of theprinting surface t will take place in the direction trans? verse to thecarrier.

The carrier in the left side of Fig. 1 must be imagined, as that of Fig.3, tohave one or more reinforcements 4 embedded-in the resilientmaterial, e. g. rubber, of which the carrier consists. The reinforcement4, Fig. 3, is rigidly connected The said reinforcement is prefer-' witha securing bolti, which can be inserted through a corresponding guidinghole 6 in the printing cylinder I. If the carrier is clamped to theprinting cylinder by means of the nut 'l, the rear face b of the carrierwill be tightened against the outer face 22 of the printing cylinder.Hereby the carrier will be deformed, so that the printing surface t willlie on a cylindrical surface of revolution with the same or-practicallythe same axis as the printing cylinder.

The presupposition of the printing surface being correct and lying onthesaid cylindrical surface of revolution is that the radii R and r ofcurvature are correctly suited to each other and in relation to theradius of curvature V of the printing cylinder, but this will cause nodifficulties in practice. It isconsidered by and for itself also apresupposition thatthe thickness of the type form is taken intoconsideration, as the said thickness will determine the stretching ofthe printing surface t when the type form degree to whichthe printingsurface t is broken.

On the amxture of the type form to the outer surface of the carrier thetype will be bent with a neutral line situated a little below half theheight of the type form. The thickness of the carrier is determined bythe radii R. and r and chiefly decides the compression of the printingsurface t of the type form on the aflixture of the carrier to theprinting cylinder. During this aflixture the carrier 2 will be bent witha neutral line situated alittle above half the height of the carrier, asit must be remembered that during this bending the carrier and the typeform form a connected whole.

The method according to the above described performance of the inventionthus is that the printing surface t of the type is'first produced whilethe type form is plane. The so produced type form (which is plane andcorrect) is then stuck to the curved outer surface 1 of the carrier,whereby the printing surface t will be deformed and stretched in thedirection indicated in Fig. 2 by the double arrow 8, while it is notdeformed in the direction of the double arrow 9. By the fixation of thecarrier with the rear face b pressed against the outer face 1 of thecylinder the said deformation of the printing surface will be.

nullified.

The printing takes place in the same way as ordinary rotary printing,and after the printing the carriers 2 may be removed from the printingcylinder and replaced by other carriers 2 with other type forms 3. Thecarriers removed from Iii vided each with. a securing bolt 5. Ifdesired,

the reinforcement may take the form of a single long rail with a numberof bolts 5. The bolts 5 and the corresponding, guiding holes 6 in theprinting cylinder ensure that the carriers-2 and, with them, thetypeforms will assume correct positions onthe printing cylinder and inrelation to each other, as a considerable number of carriers are, as arule, arranged on one and the correspondingly exact.

same printing cylinder, e. g. when printing newspapers a series ofcarriers corresponding to one or more columns side by side.

The rectangular field l shown in Fig. 2 may for instance be the printingsurface for a map or another print, on which measures are to be taken,or which must for some other reason be This is obtained by the two abovementioned oppositely directed deformations of the printing surface t,which are so suited as very exactly to nullify each other.

Fig. 1 shows two different constructions of carriers with type formsthereon, the printing surfaces of which are designated by t. Common tothe said three carriers 2 is that their lateral surfaces are so formedthat they will not meet each other until the rear faces b meet the outersurface 2) of the cylinder. Then the lateral faces will meet each otheralong the planes indicated by the lines S-S in Fig. 1.

The rear faces b need not have the shape of cylindrical surfaces ofrevolution, and in Fig. 1

the right carrier indicates that the rear face b may be composed ofplane pieces, so that the rear face has only substantially the sameshape as the rear faces of the other carriers shown.

On the carrier shown in the right side of Fig. 1 the outer surface y hasa smaller area than the corresponding outer surface of left carrier inthis figure. It may insome cases be advantageous thus to reduce theouter surface of the carrier to give it the same dimensions and form asthe bottom of the type form to be applied, e. g. stuck, to the outersurface of the carrier. This is particularly important .in the printingof labels, trade marks or similar print with e. g. circular outline. Thesticking-on is facilitated and correct sticking-on ensured, when theoutlines of the two parts correspond with each other.

It is supposed in the above that the outer surface 12 of the printingcylinder forms a cylindrical surface of revolution, but this is notnecessary, as the carriers 2 may as well have a rear face intended to bepressed against an outer surface of a printing cylinder of other form.By way of example only Figs. .4 and indicate that the outer face of theprinting cylinder may be waved and have concave or convex faces, againstwhich the rear faces b of the carriers are tightened. If the outersurface 12 of the cylinder, instead of being cylindrical, is presumed tobe shaped with a plane surface underneath each individual carrier, thenthis will not make any difference, provided that the rear faces I) onthe carriers are given a slightly lesser degree of curvature. Expressedin other words, it will not alter the effect, if the low degree ofcurvature on the-cylinder underneath the carrier is imagined as being,cut away from the cylinder and instead transferred to the rear face ofthe carrier. The cylinder may, instead of having a plane surfaceunderneath'each individual carrier, be presumed to be of a shape asshown in Fig. 5. Here the cylinder possesses underneath each individualcarrier a curved elevation and in this case a corresponding portionshall be imagined as being cut off from the rear face of the carriersshown in Fig. 1. Fig. 4 shows the cylinder provided with concavitiesunderneath the individual carriers, and in this case the concavities inthe cylinder shall be imagined as being neutralised by the addition ofthe corresponding portions to the rear face of the carriers. Thosecarriers which shall correspond to the-cylinder in Fig. 4 will thusappear with a rear face almost plane. Nothing inherently prevents theouter surface of the printing cylinder being so shaped that -thecarriers must be curved in a direction opposite to that shown in Fig. 1or, possibly, so that the concavities of their outer and rear faces faceeach other.

If the carriers 2 are not to lie close to each other as shown in Fig. 1their lateral faces may be parallel to the axis of the bolt 5, asindicated in Fig. 3 by dotted lines.

The method and devices, which are described, in the above substantiallyin connection with normal printing, may be employed in every kind ofrotary printing, where it is important to produce print without thedeformation occurring from the otherwise normal bendingof the type formto suit it to the printing cylinder. The invention is applicable torotary printing machines for industrial use and for printing of allconceivable prints on the most varying industrial products, as it is agreat advantage that a carrier with its printing surface may be quicklyremoved from the cylinder and replaced by another carrier with anotherprinting surface. Owing to the guiding holes 5 of the cylinder thischange of printing surfaces can take place with absolute certainty thata correct position of the carrier on the printing cylinder will alwaysbe secured.

- Fig. 6 shows diagrammatically a rotary printing press built forthe'printing of labels or like marks on a thin aluminium strip fromwhich blanks are subsequently to be stamped for bottle capsules. Thetype forms are on the machine shown in Fig. 6 afflxed on the printingcylinders.

by the process according to the invention and by the means through whichthis process is performed, more particularly the carriers 2. In Fig. 6,5| denotes the machine's frame. 52 is a cylinder or pin upon which hasbeen inserted a wound coil 53 of that metal strip upon which the machineshall imprint the labels or like markings. The metal strip 54 proper isadvanced, as shown by Fig. 6, through three consecutive pairs ofcylinders consisting of bottom cylinders 55 and top printing cylinders lcorresponding to those shown in Fig. 1. Each of these printingcylindersis in Fig. 6 seen to have aflixed eight carriers 2 on whoseouter sides type forms are attached corresponding to the type forms t inFig. 1. The number of cylinder pairs may be increased or reduced, allaccording to the number of colours with which it is desired to print.

All type forms on the carriers 2 on the printing cylinder l on the lefthand side of Fig. 6 are identical and aflixed identically and colour isapplied to all of them from the colour cylinder 56. The printingcylinder on the left hand side in Fig. 6 must e. g. be imagined asimprinting upon the metal strip 54 the ring 51 shown in Fig. 7, in redcolour.

Similarly, the middle printing cylinder l shown in Fig. 6 must beimagined as printing, e. g. the square 58 shown in Fig. 7, in yellowcolour.

Similarly, the right hand printing cylinder I shown in Fig. 6 must beimagined as printing, e. g. the spot 59 shown in Fig. '7, in bluecolour.

In order to ensure that all the imprints 51, 58 and 59 will be appliedin the exact relationship to one another, and that the subsequentstamping out of the bottle capsule blanks shall take place in thecorrect manner so that the imprint comes out in the correct position onthe blanks, the metal strip 54, Fig. 7, is usually furnished with guideholes 60, the printing machines advancement cylinders, i. e. the bottomcylinders 55, being at the same time provided with corresponding guidepins which engage with the holes in the strip 54.

The printed and, possibly, by special means dried strip 54 is finallywound up into a coil 6| on a cylinder or pin 62.

I claim:

1. A methodfor producing a cylindrical printing surface comprisingdistorting a plane type form in one direction by permanently amxing saidform to a curved resilient carrier and then again distorting said formon said carrier in the opposite direction in applying said form andcarrier to the printing cylinder.

2. A method for producing a cylindrical printing surface comprisingstretching a plane type form by permanently amxing said form on a curvedresilient carrier and then compressing said type form on said carrier inapplying said form and carrier to the printing cylinder.

3. A method for producing a cylindrical printing surface. comprisingdistorting a plane type form by permanently afiixing said form on acurved surface of a resilient carrier having a radius of curvature lessthan that of the final printing surface and then again distorting saidform in applying said form and carrier to the printing cylinder.

4. Acylindrical printing surface comprising a printing cylinder, acarrier carrying a distorted type form permanently aflixed thereon andsaid carrier being of resilient material and of such form so that whenapplied to said cylinder the outer surface thereof carrying said typeform is compressed to neutralize approximately the distortion of saidtype form. 5. A cylindrical printing surface comprising a printingcylinder, a carrier having a distorted type form permanently affixed ontheouter surface thereof and said carrier being of resilient materialand having a contour at the surface contacting said cylinder differentfrom the printing cylinder surface so that when applied thereto theouter surface is compressed to neutralize approximately the distortionof said type form.

6. A cylindrical printing surface comprising a printing cylinder, acarrier having a distorted type form permanently aflixed on the outersurface thereof and said carrier being of resilient material and havinga curved contour at the surface thereof contacting said cylinder with aradius of curvature less than the radius of curvature of said printingcylinder so that when applied to said printing cylinder said outersurface is compressed.

7. A cylindrical printing surface comprising a I printing cylinder, a,carrier having a distorted type form permanently aflixed on the outersurface thereof and said carrier being of resilient material and havinga curved contour at the surface thereof contacting said cylinder with aradius of curvature less than the radius of curvature of said printingcylinder to such an extent that when applied to said printing cylindersaid outer surfaceis compressed to neutralize approximately thedistortion of said type form. 8. A cylindrical printing surfacecomprising a printing cylinder and a resilient type form carrier mountedthereon with the outer surface thereof in a state of compression.

9. A cylindrical printing surface comprising a printing cylinder, aresilient type form carrier mounted thereon with the outer surfacethereof in a state of compression, a reinforcement embedded in saidcarrier and means for clamping said carrier to said cylinder cooperatingwith said reinforcement.

10. A cylindrical printing surface comprising a printing cylinder, aresilient type form carrier mounted thereon with the outer surfacethereof in a state of compression, a. reinforcement embedded in saidcarrier and means for clamping said carrier to said cylinder cooperatingwith said reinforcement, and guiding means in. said A0 cylindercooperating with said clamping means. HENRY ARNOLD SKOV.

